Patients contracted the illness after being given spinal injections of the steroid methylprednisolone acetate. Photograph: Kristin M Hall/AP

Eleven people have now died from a fatal outbreak of meningitis, with 119 now sick with the illness, according to health officials. Experts said they could be seeing new cases as late as December, two months later than previously thought. It is long waiting game for some of the 13,000 people who may have received medication from the suspected source of the illness to get the all-clear.

Some of the patients have had strokes as a result of the infection, but few details were available.

Officials have linked the rare form of meningitis, which is not contagious, to a contaminated steroid injection produced by New England Compounding Center in Massachusetts. At least one contaminated vial was found at the company, in an ongoing investigation by the Food and Drug Administration.

Up to 13,000 people may have received the steroid, commonly used as a spinal injection to treat back pain, from NECC between May 21 and September 25, the CDC said. It is unclear how many of the shots were infected, however. The figure includes not only people who got spinal injections, believed to be most at risk, but those who received injections in other parts of the body, such as knees or shoulders.

At a press conference on Tuesday, Dr John Dreyzehner said those who got the tainted shot might not show symptoms for up to three months later, according to Nashville Public Radio.

Officials had thought people exposed to the contaminated steroid were in the clear after a month. Symptoms took on average 16 days to develop, but Dreyzehner said one case took 42 days. So, to be safe, the window for those looking out for symptoms could remain open as long as three months.

Sue Manor, 66, of Hendersonville, spoke of her "agonising" wait for the all-clear. One of the Saint Thomas pain patients who received a steroid injection, Manor told the (Nashville) Tennessean on Tuesday that she became anxious and believed she had symptoms.

"I had a couple of days where I had a headache and my neck was stiff," she said. "Intellectually, I knew it was stress bringing it on. But there is the slightest possibility – or even a good possibility – that it could be the early onset of meningitis on my system."

By Monday, she said, she was feeling better, but, following Tuesday's warning, Manor may be among patients who have a longer wait for the all-clear than they first thought.

Fungal meningitis is treated with high-dose anti-fungal medications, usually given intravenously in a hospital.

A second kind of fungus is now thought to be the main culprit in the rapidly evolving outbreak. Officials first said the contamination was from a mold called Aspergilus. Now, state health commissioner Dreyzehner said they had identified a second variety.

"Our ongoing investigation indicates Exserohilum is the primary fungal infection affecting patients in Tennessee – a fungus so rare that most physicians never see it in a lifetime of practising medicine," he said.

The antifungal medicine would still work against the second fungus, he said.

An update from the Centers for Disease Control and Prevention, issued on Tuesday afternoon, included New Jersey on the list of states in which at least one person has contracted the illness.

Other states with confirmed cases includes Florida, Indiana, Minnesota, North Carolina and Ohio.

Officials from the FDA have told doctors, hospital and medical clinics to contact thousands of patients who may have received in infected dose to look out for symptoms.

NECC recalled the preservative-free steroid called methylprednisolone acetate that was sent to clinics in 23 states and later recalled everything it makes.

Last week, it surrendered its license to operate until the ongoing FDA investigation into the contamination is complete.

Health officials say 75 medical facilities in 23 states received the contaminated steroid injections from NECC.

Infected patients have developed a variety of symptoms including fever, new or worsening headache, nausea, and "new neurological deficit [consistent with deep brain stroke]," the CDC said in a news release. Some of these patients' symptoms were very mild in nature. Cerebrospinal fluid from these patients has shown findings consistent with meningitis, the agency said.